Round Multi-Blade Backdraft Damper
Round multi-blade backdraft damper, also known as circular multi-blade gravity non return damper, is a high-stability ventilation check valve for all types of round duct HVAC systems. Its multi-blade layout ensures balanced airflow and superior shut-off effect, making it ideal for large-size circular pipelines where single-blade dampers cannot operate steadily. Made of durable anti-corrosion metal materials with reinforced round frame, this gravity-operated damper requires no power supply and nearly zero daily maintenance. Easy to install on round ductwork, fan outlets and ceiling exhaust terminals, it is widely adopted in household ventilation, commercial air conditioning and general industrial air extraction systems for stable anti-backdraft protection.
Product Description
The Round Multi-Blade Backdraft Damper is designed to prevent reverse airflow in round HVAC and ventilation duct systems. It features multiple gravity-operated blades that open automatically when air flows in the intended direction and close when airflow stops or reverses. Compared with single-blade models, the multi-blade structure provides more stable operation, improved closing performance, and better suitability for larger duct diameters.
This damper is widely used in residential, commercial, and light industrial ventilation systems to block outside air, dust, insects, and unwanted backflow from entering the duct line. The reinforced frame construction improves overall strength, while the multi-blade arrangement helps maintain good airtightness and dependable non-return performance.
Manufactured from galvanized steel, aluminum, or other optional materials, the damper offers durability, low maintenance, and easy installation in round duct connections, exhaust outlets, and fan systems.
Key Features
- Multi-Blade Design Multiple blades provide stable opening and closing performance
- Backdraft Prevention Effectively prevents reverse airflow in round duct systems
- Gravity Operated Blades open automatically under airflow and close when airflow stops
- Reinforced Frame Strong frame structure improves durability and installation stability
- Good Airtightness Multi-blade arrangement helps reduce leakage and improve shut-off performance
- Low Maintenance Simple mechanical structure without motor or complex control parts
- Round Duct Compatibility Suitable for circular duct and pipe connections
- Durable Construction Available in galvanized steel, aluminum, or stainless steel optional
Applications
- Residential ventilation systems
- Commercial HVAC systems
- Exhaust air duct systems
- Inline fan outlets
- Wall or ceiling exhaust terminations
- General building ventilation
- Air extraction systems
- Round duct reverse airflow protection
Technical Specifications
| Parameter | Value / Option |
| Product Name | Round Multi-Blade Backdraft Damper |
| Type | Gravity Operated Non Return Damper |
| Shape | Round / Circular |
| Blade Structure | Multi-blade |
| Material | Galvanized Steel / Aluminum / Stainless Steel optional |
| Frame Type | Reinforced circular frame |
| Operation | Automatic opening by airflow, gravity closing |
| Installation | Round duct connection / exhaust outlet installation |
| Function | Prevent reverse airflow |
| Feature | Good airtightness / stable operation |
| Application | HVAC / Ventilation / Exhaust systems |
| OEM / ODM | Available |
